For rebreather dives, Suunto EON Steel should be used as a backup device only. The primary control and monitoring of your gases should be done through the rebreather itself.

Closed-circuit gases

On a rebreather dive, you need at minimum two closed-circuit gases: one is your pure oxygen tank, and the other is a diluent. You can define additional diluents as needed.

The correct oxygen and helium percentages of the diluent gas(es) in your diluent cylinder(s) must always be entered into the dive computer (or through DM5) to ensure correct tissue and oxygen calculation. Diluent gas(es) used on a rebreather dive are found under CC gases in the main menu.

Open-circuit gases

As with diluents, you must alway define the correct oxygen and helium percentages of bailout gas(es) for all your cylinders (and additional gases) to ensure correct tissue and oxygen calculation. Bailout gases for a rebreather dive are defined under OC gases in the main menu.

Setpoints

CCR mode has two setpoint values, low and high. Both are configurable:

Low setpoint: 0.4 – 0.9 (default: 0.7)

High setpoint: 1.0 – 1.6 (default: 1.3)

Typically you do not need to modify the default setpoint values. However, you can change them as needed either in DM5 or under the main menu.

To change setpoint values in Suunto EON Steel:

While in surface state, keep middle button pressed to enter main menu.

Scroll to Setpoint with the upper button and select with the middle button.

Scroll to Low setpoint or High setpoint and select with the middle button.

Adjust the setpoint value with the lower or upper button and accept with the middle button.

Keep middle button pressed to exit menu.

Setpoint switching

Setpoints can be switched automatically according to depth. By default the low setpoint switch depth is 4.5 m (15 ft), and the high setpoint switch depth is 21 m (70 ft).

The auto setpoint switching is off by default for the low setpoint and on for the high setpoint.

To change auto setpoint switching in Suunto EON Steel:

While in surface state, keep middle button pressed to enter main menu.

Scroll to Setpoint with the upper button and select with the middle button.

Scroll to Switch low or Switch high and select with the middle button.

Adjust the depth value for the setpoint switch with the lower or upper button and accept with the middle button.

Keep middle button pressed to exit menu.

Popup notifications indicate when the setpoint is switched.

During a rebreather dive, you can also switch to a custom setpoint at any time.

To change to a custom setpoint:

While diving in CCR mode, keep middle button pressed to enter main menu.

Scroll to Custom setpoint and select with the middle button.

Adjust the setpoint value as needed with the lower or upper button and accept with the middle button.

A popup notification confirms the custom setpoint switch.

NOTE:

When you change to a custom setpoint, the automatic setpoint switching is turned off for the remainder of the dive.

Bailouts

If at any point during a rebreather dive you suspect a malfunction of any sort, you should switch to a bailout gas and abort the dive.

To change to a bailout gas:

Keep the middle button pressed to enter main menu.

Scroll to OC gases and select with middle button.

Scroll to the desired bailout gas and select with the middle button.

After a bailout gas is selected, the setpoint field is replaced with the pO2 value of the selected open-circuit gas.

If the malfunction is rectified or the dive situation otherwise normalizes, you can switch back to a diluent using the same procedure as below, but selecting from CC gases.